These two rides were to compare 2 different wheels/tires. This was with the 27.5" DT Swiss wheels with Pirelli Cinturato 50mm tires. It was 30 minutes out (with an intermittent tail wind). I tried to average the same watts with both wheel sets -- 134 going out and 135 coming back. On the way back I marked 30 minutes at 135 watts with a lap, then continued at about 132 or 133 back to the start. From the speed graph you can see there was a strong tail wind in the first part of the ride where the trail was in a narrow canyon. This was stronger for this (the second/later) ride. You can also see the effect of altitude on my heart rate in this second ride. It migh also be that I am not recovered from last Saturdays 80 mile ride -- with 60 hill sprints. The results showed the tires were almost identical. The average speed for the 30 minute out and 30 minute back was 16.6 for the Bontrager Aeolus RSL 37's with Continental Terr speeds and 16.5 for the 650B DT Swiss set with the Pirelli tires.